Due to the development of software and hardware and the development of communication technology, many devices have been developed as portable devices. Not only the smart phones, but also many other devices such as laptop Personal Computers (PCs), tablet PCs and MP3 players support a Wireless Local Area Network (WLAN), and the number of spots where the WLAN is available has been on the rise. For example, many Access Point (AP) networks are installed in the public places such as cafes, subway stations and airports, allowing users to access the WLAN anywhere anytime. Therefore, the Internet traffic has increased exponentially.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.